# BCS-BEC crossover on the two-dimensional honeycomb lattice.

@article{Zhao2006BCSBECCO, title={BCS-BEC crossover on the two-dimensional honeycomb lattice.}, author={Erhai Zhao and Arun Paramekanti}, journal={Physical review letters}, year={2006}, volume={97 23}, pages={ 230404 } }

The attractive Hubbard model on the honeycomb lattice exhibits, at half filling, a quantum critical point between a semimetal with massless Dirac fermions and an s-wave superconductor (SC). We study the BCS-BEC crossover in this model away from half filling at zero temperature and show that the appropriately defined crossover line (in the interaction-density plane) passes through the quantum critical point at half filling. For a range of densities around half filling, the "underlying Fermi… Expand

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#### References

SHOWING 1-10 OF 31 REFERENCES

Semi-Metal-Insulator Transition of the Hubbard Model in the Honeycomb Lattice

- Physics
- 1992

Using quantum Monte Carlo and finite-size scaling for the Hubbard model, we find evidence of a zero-temperature transition between the nonmagnetic semi-metal and an antiferromagnetic insulator in the… Expand

Mott-Hubbard transition and antiferromagnetism on the honeycomb lattice

- Physics
- 1996

AbstractThe Hubbard model is investigated for a halffilled honeycomb lattice, using a variational method. Two trial wave functions are introduced, the Gutzwiller wave function, well suited for… Expand

BCS-BEC crossover of collective excitations in two-band superfluids

- Physics
- 2005

We use the functional integral approach to study low energy collective excitations in a continuum model of neutral two-band superfluids at T=0 for all couplings with a separable pairing interaction.… Expand

Antiferromagnetism of the Hubbard Model on a Layered Honeycomb Lattice – Is MgB2 a Nearly-Antiferromagnetic Metal? –

- Physics
- 2001

As a model for the B 2 p z bands of MgB 2 , a half-filled Hubbard model on a honeycomb lattice is studied, and a possibility of an antiferromagnetism (AF) at the ground state is examined by Monte… Expand

Interactions and phase transitions on graphene's honeycomb lattice.

- Physics, Medicine
- Physical review letters
- 2006

The Hubbard model in the large-N limit is shown to have a semimetal-antiferromagnetic insulator quantum critical point in the universality class of the Gross-Neveu model, and its consequences for various physical quantities are examined. Expand

BEC–BCS crossover in an optical lattice

- Physics
- 2006

We present the microscopic theory for the BEC-BCS crossover of an atomic Fermi gas in an optical lattice, showing that the Feshbach resonance underlying the crossover in principle induces strong… Expand

BCS BEC crossover: From high temperature superconductors to ultracold superfluids

- Physics
- 2005

Abstract We review the BCS to Bose–Einstein condensation (BEC) crossover scenario which is based on the well known crossover generalization of the BCS ground state wavefunction Ψ 0 . While this… Expand

Berezinskii-Kosterlitz-Thouless transition and BCS-Bose crossover in the two-dimensional attractive Hubbard model

- Physics
- 2004

We study the two-dimensional attractive Hubbard model using the mapping onto the half-filled repulsive Hubbard model in a uniform magnetic field coupled to the fermion spins. The low-energy effective… Expand

Ground-state and finite-temperature signatures of quantum phase transitions in the half-filled Hubbard model on a honeycomb lattice

- Physics
- 2005

We investigate ground state and finite temperature properties of the half-filled Hubbard model on a honeycomb lattice using quantum Monte Carlo and series expansion techniques. Unlike the square… Expand

Critical temperature for the two-dimensional attractive Hubbard model

- Physics
- 2004

The critical temperature for the attractive Hubbard model on a square lattice is determined from the analysis of two independent quantities, the helicity modulus, $\rho_s$, and the pairing… Expand